/*!
 * Crypto-JS v1.1.0
 * http://code.google.com/p/crypto-js/
 * Copyright (c) 2009, Jeff Mott. All rights reserved.
 * http://code.google.com/p/crypto-js/wiki/License
 */
(function () {

// Shortcut
    var util = Crypto.util;

// Inner state
    var x = [],
        c = [],
        b;

    var Rabbit = Crypto.Rabbit = {

        /**
         * Public API
         */

        encrypt: function (message, password) {

            var

            // Convert to bytes
                m = util.stringToBytes(message),

            // Generate random IV
                iv = util.randomBytes(8),

            // Generate key
                k = Crypto.PBKDF2(password, util.bytesToString(iv), 16, {asBytes: true});

            // Encrypt
            Rabbit._rabbit(m, k, util.bytesToWords(iv));

            // Return ciphertext
            return util.bytesToBase64(iv.concat(m));

        },

        decrypt: function (ciphertext, password) {

            var

            // Convert to bytes
                c = util.base64ToBytes(ciphertext),

            // Separate IV and message
                iv = c.splice(0, 8),

            // Generate key
                k = Crypto.PBKDF2(password, util.bytesToString(iv), 16, {asBytes: true});

            // Decrypt
            Rabbit._rabbit(c, k, util.bytesToWords(iv));

            // Return plaintext
            return util.bytesToString(c);

        },


        /**
         * Internal methods
         */

        // Encryption/decryption scheme
        _rabbit: function (m, k, iv) {

            Rabbit._keysetup(k);
            if (iv) Rabbit._ivsetup(iv);

            for (var s = [], i = 0; i < m.length; i++) {

                if (i % 16 == 0) {

                    // Iterate the system
                    Rabbit._nextstate();

                    // Generate 16 bytes of pseudo-random data
                    s[0] = x[0] ^ (x[5] >>> 16) ^ (x[3] << 16);
                    s[1] = x[2] ^ (x[7] >>> 16) ^ (x[5] << 16);
                    s[2] = x[4] ^ (x[1] >>> 16) ^ (x[7] << 16);
                    s[3] = x[6] ^ (x[3] >>> 16) ^ (x[1] << 16);

                    // Swap endian
                    for (var j = 0; j < 4; j++) {
                        s[j] = ((s[j] << 8) | (s[j] >>> 24)) & 0x00FF00FF |
                            ((s[j] << 24) | (s[j] >>> 8)) & 0xFF00FF00;
                    }

                    // Convert words to bytes
                    for (var b = 120; b >= 0; b -= 8)
                        s[b / 8] = (s[b >>> 5] >>> (24 - b % 32)) & 0xFF;

                }

                m[i] ^= s[i % 16];

            }

        },

        // Key setup scheme
        _keysetup: function (k) {

            // Generate initial state values
            x[0] = k[0];
            x[2] = k[1];
            x[4] = k[2];
            x[6] = k[3];
            x[1] = (k[3] << 16) | (k[2] >>> 16);
            x[3] = (k[0] << 16) | (k[3] >>> 16);
            x[5] = (k[1] << 16) | (k[0] >>> 16);
            x[7] = (k[2] << 16) | (k[1] >>> 16);

            // Generate initial counter values
            c[0] = util.rotl(k[2], 16);
            c[2] = util.rotl(k[3], 16);
            c[4] = util.rotl(k[0], 16);
            c[6] = util.rotl(k[1], 16);
            c[1] = (k[0] & 0xFFFF0000) | (k[1] & 0xFFFF);
            c[3] = (k[1] & 0xFFFF0000) | (k[2] & 0xFFFF);
            c[5] = (k[2] & 0xFFFF0000) | (k[3] & 0xFFFF);
            c[7] = (k[3] & 0xFFFF0000) | (k[0] & 0xFFFF);

            // Clear carry bit
            b = 0;

            // Iterate the system four times
            for (var i = 0; i < 4; i++) Rabbit._nextstate();

            // Modify the counters
            for (var i = 0; i < 8; i++) c[i] ^= x[(i + 4) & 7];

        },

        // IV setup scheme
        _ivsetup: function (iv) {

            // Generate four subvectors
            var i0 = util.endian(iv[0]),
                i2 = util.endian(iv[1]),
                i1 = (i0 >>> 16) | (i2 & 0xFFFF0000),
                i3 = (i2 << 16) | (i0 & 0x0000FFFF);

            // Modify counter values
            c[0] ^= i0;
            c[1] ^= i1;
            c[2] ^= i2;
            c[3] ^= i3;
            c[4] ^= i0;
            c[5] ^= i1;
            c[6] ^= i2;
            c[7] ^= i3;

            // Iterate the system four times
            for (var i = 0; i < 4; i++) Rabbit._nextstate();

        },

        // Next-state function
        _nextstate: function () {

            // Save old counter values
            for (var c_old = [], i = 0; i < 8; i++) c_old[i] = c[i];

            // Calculate new counter values
            c[0] = (c[0] + 0x4D34D34D + b) >>> 0;
            c[1] = (c[1] + 0xD34D34D3 + ((c[0] >>> 0) < (c_old[0] >>> 0) ? 1 : 0)) >>> 0;
            c[2] = (c[2] + 0x34D34D34 + ((c[1] >>> 0) < (c_old[1] >>> 0) ? 1 : 0)) >>> 0;
            c[3] = (c[3] + 0x4D34D34D + ((c[2] >>> 0) < (c_old[2] >>> 0) ? 1 : 0)) >>> 0;
            c[4] = (c[4] + 0xD34D34D3 + ((c[3] >>> 0) < (c_old[3] >>> 0) ? 1 : 0)) >>> 0;
            c[5] = (c[5] + 0x34D34D34 + ((c[4] >>> 0) < (c_old[4] >>> 0) ? 1 : 0)) >>> 0;
            c[6] = (c[6] + 0x4D34D34D + ((c[5] >>> 0) < (c_old[5] >>> 0) ? 1 : 0)) >>> 0;
            c[7] = (c[7] + 0xD34D34D3 + ((c[6] >>> 0) < (c_old[6] >>> 0) ? 1 : 0)) >>> 0;
            b = (c[7] >>> 0) < (c_old[7] >>> 0) ? 1 : 0;

            // Calculate the g-values
            for (var g = [], i = 0; i < 8; i++) {

                var gx = (x[i] + c[i]) >>> 0;

                // Construct high and low argument for squaring
                var ga = gx & 0xFFFF,
                    gb = gx >>> 16;

                // Calculate high and low result of squaring
                var gh = ((((ga * ga) >>> 17) + ga * gb) >>> 15) + gb * gb,
                    gl = (((gx & 0xFFFF0000) * gx) >>> 0) + (((gx & 0x0000FFFF) * gx) >>> 0) >>> 0;

                // High XOR low
                g[i] = gh ^ gl;

            }

            // Calculate new state values
            x[0] = g[0] + ((g[7] << 16) | (g[7] >>> 16)) + ((g[6] << 16) | (g[6] >>> 16));
            x[1] = g[1] + ((g[0] << 8) | (g[0] >>> 24)) + g[7];
            x[2] = g[2] + ((g[1] << 16) | (g[1] >>> 16)) + ((g[0] << 16) | (g[0] >>> 16));
            x[3] = g[3] + ((g[2] << 8) | (g[2] >>> 24)) + g[1];
            x[4] = g[4] + ((g[3] << 16) | (g[3] >>> 16)) + ((g[2] << 16) | (g[2] >>> 16));
            x[5] = g[5] + ((g[4] << 8) | (g[4] >>> 24)) + g[3];
            x[6] = g[6] + ((g[5] << 16) | (g[5] >>> 16)) + ((g[4] << 16) | (g[4] >>> 16));
            x[7] = g[7] + ((g[6] << 8) | (g[6] >>> 24)) + g[5];

        }

    };

})();
